pump air

Hey brothers, I've been lurking in these forums for a long while and have some experience. I've used Bathmate for a long time, but I grew so tired of the hassle of getting in the tub or the shower all the time, so I got a generic pump to try out before I order one of the MOS products. The...

does the size of cylinder vs penis size make any difference? and also besides the balls getting sucked in obviously. does larger cylinder affect anything when pumping?